The temperature at which a circuit is operating is a key performance consideration in many applications. For example, the performance of various semiconductor devices may vary widely across hot and cold temperatures. Thus, semiconductor manufacturers often guarantee circuit performance only for a predetermined temperature range. Because temperature can be a key performance consideration, some applications actively measure and monitor temperature. Devices known as thermistors are known to have a resistances that vary over temperature. Accordingly, some applications measure the resistance of a thermistor in order to track the approximate temperature at which a circuit is operating.